Input device that sets button baseline value or panel baseline value to initial value, depending on whether touch operation on touch button based on electrostatic capacitance is valid, and image forming apparatus

An input device includes a touch panel, a touch button, a first measurement device, a second measurement device, a first detection device that detects a touch position on the touch panel, based on a difference between the electrostatic capacitance measured by the first measurement device and a panel baseline value, a second detection device that detects a touch operation on the touch button, based on a difference between the electrostatic capacitance measured by the second measurement device and a button baseline value, an error decision device that decides that the touch operation is an error, when the touch operation satisfies a predetermined condition, and a controller that sets the button baseline value to an initial value, when the error decision device has identified an error, and sets the panel baseline value to an initial value, when the error decision device has not identified an error.